听一段材料，回答下面几个小题。
Which of the following can be found in the national parks?
A. Animals.
B. Lakers.
C. Both A and B.
How do they go to the camp sites?
A. By cycling.
B. By walking.
C. By driving.
Why do people enjoy camping?
A. Because they can relax and enjoy a quiet life.
B. Because they like the conveniences there.
C. Because they can live in tents in the camp sites.
What conveniences do campers in trailers have?
A. They can have a party there.
B. They have electricity and hot water.
C. They can swim in them.